US2585927A - Camera and stand therefor - Google Patents

Description

Feb. 19, 1952 GELB 2,585,921

CAMERA AND STAND THEREFOR Filed April 29, 1949 4 Sheets-Sheet 1 IN VEN TOR.

BY Saw/(mal $254 Feb. 19, 1952 H. GELB 2,585,927

CAMERA AND STAND THEREFOR Filed A ril 29, 1949 4 Sheets-SheetZ IN VEN TOR.

@MM 5 W AiIoI'IZaVS Feb. 19, 1952 H. GELB 2,585,927 CAMERA AND STAND THEREFOR Filed April 29, 1949 4 Sheets-Sheet :5

H. GELB CAMERA AND STAND THEREFOR Feb. 19, 1952 4 Sheets-Sheet 4 Filed April 29, 1949 Patented Feb. 19, 1952 Herbert Gelb, New York, N. Y., assignor toJoseph Gelb Company, New York,,N..Y...

Application-April zSi, 1949;= seiial-'No.:90;311

241Claims.

.1. 'Ihe invention relates to the artcof photography.

Broadly described, the general object .of: the invention is to provide a heavy dut-ystationary camera of novel construction and :adapted to produce extremely accurate work.

A particular object of the invention is to provide a novel heavy-duty, stationary suspended camera capable of producingphotoprintin'g of great accuracy even when installed in' a-building subject to considerable vibration. In connection with this object-thepresent invention contemplates a simple, relatively inexpensive, and. novel construction for -a supportfor the camera obscura and. sits cooperating: parts, which support ..makes possible a .reaction to such vibration (as .a unit of the entire combination of working .photographicparts of the invention. A particular.purpose here, of course, is to'avoid independent. vibration of thesubj cot-mounted on a copy board, of the lens and shutter arrangement, of ;a half-tone "screen, when .used, and of the sensitized -plate desired "to. .be .photoprinted. While independent vibration .of .the .fiood .lights in photography is, of course, not .desirable,.it 11's not of great importance; however, the combination of thepresent invention verymaterially reduces even this independent vibration. Those versed in photography as employedinlithography andother printing arts, ast-well as any workers in photography, will readilyunderstand the value of protecting; photographic equipment from externallyapplied shocks.

The support construction of the present invention is such that the complete camera obscura, with the sensitized plate to be photoprinted, and, when half tone work is required, the screen, and the copy board and its subject are rigidly, although adjustably, connected together as a common unit, this unit floating-on a base structure. The obvious advantage \is that the various parts of the photographic equipment do notchange position with respect to each other in accordance with shocks transmitted by the floor of a building to said-base structure.

Another object of the invention is to provide improved means for varying the photoprint scale withrespect to that of "the subject mounted on the'copy board," and for preventing overthrow or back lash upon setting the copy board with respect-to'thecamera lens. It is wellknownin the" art-that building vibration and loosely cooperating parts 'of'a stationarycamera frequently operate'to upset'a fine focal adjustment which" has been-"carefullymadeprior'to exposure. Thus the,

present einventionicontemplates, means -f or vary- :ing: the distance-betweenthecamera lens and the .copy aboard; forgpurposespf enlargement and. re-

(motion; which :means operate not only-to prevent overthrow zand back :lash but also to;prevent .change-,of;:the:selected distance setting due to vibration.

vAnotherxobject of the 1invention-.-is to provide suchya-rcameraahaving means accessible to an operator ain the dark room, against which i the camera abuts, whereby ;-the distance between. the cameralens'and thecopyaboard may beradjusted both by .electricpowerand. by hand, said means comprisingjndicators of thedistancesetting and vernier :precision' adjustments whereby the operatorxm'ay .blindl-y make an extremely;[accurate adi'stancetadjustment;

Anotherrobjectiofethetinvention is to provide such: a; cameraewherein both the camera obscura .and ethe.:copy-board; are suspended on .a :rigid bridgestructureifloating, on aplurality of resilient supports.

=Aifurtheriobject of the invention is to provide 'on-ztsuchia; bridge sstr ucture means for electrically varying rthersdistance between the lens and copy ;board;so that the entire :assembly; of photographic parts hand. their ,prime movers are together duty, stationary camera for .use by lithograph'ers and others in .the printing arts, which. is adapted to bezinstalledso that its screen and plate magazine may forma wall of a dark.room..

.A furtherobjectof theinvention .is to provide a.photographicrapparatus whereinboth the cameralens board and .a unit comprising the copy board and floodlightso therefor are individually movable on. trolleys ridingon' abridge structure.

"These .andiurther objects will be more fully understood from. the "following description and "from .the ,drawing in which one embodiment of the invention is' illustrated.

In the drawing:

Fig. 1 'is a right side elevationltoi'the"camera.

Fig.2 is the section 2-4 of Fig. ?1,'en1arged"to 'fiftypercent over the scale of Fig. '1.

Figs. 3 and 4 together constitute a top plan view of the camera on the scale of Fig. 2.

The apparatus comprises a trestle structure which provides support for the actual camera obscura itself together with its plate, plate holder, and, where half tone engraving is desired, its half tone screen and screen holder, and where photoprinting of flexible film is desired, a vacuum board to hold the film flat, and its lens, shutter, and filter panel and flashlight; for the copy board; and for the floodlights and their carriage, as well as for all cooperating parts, more specifically described below, which, all together, make a complete horizontal type photoengraving camera of the apparatus.

In the present description the front of the camera is regarded as being to the right in Fig. 1. Thus this figure, which is a side elevational view of the camera, is a right side view; and, as it shows the camera almost in its entirety, is the most comprehensive single figure of the drawing. It will be understood that apparatus of this nature is often of considerable size, lengths up to around twenty feet and heights of about seven to eight feet not being uncommon. The particular embodiment of the invention illustrated herein is an existing camera built in accordance with the invention and is about seventeen feet long. For this reason it has been necessary to break the trestle structure vertically in the midportion to condense the side elevation of Fig. 1. It will be understood from the figure itself and from the following that nothing essential to the disclosure and the claims has been left unillustrated.

lhe sectional view of Fig. 2 and the top plan view comprising Figs. 3 and 4 are enlarged fifty percent with respect to the. scale of Fig.- 1 so that certain important parts may be shown in greater detail. The increase in scale has made it necessary to omit part of the lower half of the cross section (Fig. 2), which is immaterial insofar as full illustration of the invention is concerned since Fig. 1 adequately illustrates the missing parts of the cross section, and to use two sheets for the top plan view, Fig. 3 covering the rear portion of the apparatus and Fig. 4. the front portion thereof. Certain parts, otherwise sufficiently well illustrated in Fig. 1, are omitted in Figs. 3 and 4.

The structure is such that a vertical plane dividing the apparatus longitudinally at the center separates two halves which are very nearly exactly symmetrical, almost every part on the right side, as illustrated in Fig. 1, having a corresponding part on the left side. Where, in the drawing, any such corresponding part is not illustrated in any figure such part will be understood to have the appearance of a mirror'image of its companion part shown in Fig. 1 For example, it is assumed in Fig. 1 that the righthand floodlight completely obscures a reversed floodlight on the lefthand side of the camera.

The trestle structure is supported by six like legs, each of which is preferably asteel tube.

y l, 3, and 4. All legs are fitted within suitable footings l5, adapted to be secured in suitable manner to a floor.

Surmounting legs l and I2 is a cap plate I! rigidly secured to said legs. See Fig. 1. Likewise, surmounting legs II and I 3, on the left side of the apparatus, is another cap plate I8. See Figs. 2 and 3. Upon each cap plate are rigidly secured six resilient mounts 19 arranged in two rows of three each, as best illustrated (in dotted lines) in Fig. 3. Each mount [9 is a pedestal comprising a rigid flanged base portion 20 housing a block 2| of resilient material, such as rubber, and, within the block, a bushing 22 through which passes a mounting pin or bolt 23.

All such mounting pins or bolts of the apparatus, there being twenty of them, are referred to as 23 however, to avoid confusion in the drawing only those four mounting pins or bolts 23 visible in Fig. 2 are indexed.

The entire assembly of photographic parts of the apparatus is, as has been said, rigid but adjustable; and this assembly rests upon twenty mounts 19 associated with the twenty mounting pins or bolts 23 mentioned above, and not directly upon the six rigid legs 10-!5, inclusive. Thus the entire assembly of photographic parts floats above the legs as a rigid entity lying upon the resilient blocks 2 I.

Figs. 1 and 4 show that legs I4 and I5 are respectively surmounted by cap plates 24 and 25; each of these cap plates carries a square arrangement of four mounts IS, the mounts being, of course, rigidly secured to the plates.

Anchored by means of bolts 23 to the twelve mounts l9 at the rear of the apparatus, six of said mounts being carried by cap plate I! and the other six thereof by cap plate [8, is a rigid, transverse, box-like frame comprising two parallel channels 26 and 21 set on edge with their flanges in opposition (see Fig. 1; also, Fig. 3; Fig. 2 shows the front channel 2'! only). The channels 26 and 21 are suitably connected together within the frame structure and so form a partially enclosed housing for certain moving parts subsequently to be described.

Anchored to the four mounts IS on cap plate 24 at the front of the apparatus is a plate 28; and anchored to the four mounts IS on cap plate 25, also at the front of the apparatus, is a plate 29.

Supported by and rigidly secured to these plates is a transverse channel 30, set on edge as shown in Fig. l.

Lengthwise of the apparatus is another rigid, box-like frame comprising two parallel channels 3i and 32, the ends of which rest upon and are rigidly secured to channels 21 and 30 at the rear and front of the apparatus respectively, the channels 3| and 32 being cross connected intermediate their ends at intervals by suitable ties 33 of which one is best illustrated in Fig. 2 which includes a cross section of the lastnamed frame. The sev-- eral ties 33 are preferably castings having the shape shown in Fig. 2. Other ties 33 are seen in Figs. 3 and 4.

The frame which comprises channels 3| and 32 serves as a hanger for tracks (more particularly described below) extending from the rear to the front of the apparatus.

The manner in which the tracks are hung from the frame is best illustrated in Fig. 2. Mounted opposite each other and respectively secured to the outsides of channels 3| and 32 are like lugs 34 and 35, the arrangement described being repeated at intervals along the frame, and, as a. convenience, preferably in alignment with the stations of position of the ties 33. Each lug is vertically bored and tapped to receive a bolt 36, each bolt extending below the frame and engagmg a cross tie 31 on the extremities of which are secured horizontal bars 38 and'39 of rectangular cross section, each such'bar serving as a'traction rail (see below).

On the top of each-cross tie 31-at the righthand end thereof is a pillar block 40, and on the lefthand end thereof a similar pillar block 4|, each pillar block being rigidly secured to the cross tie. The pillar blocks are not'provided with caps. The arrangement of pillar blocks is of course understood to be repeated at intervals along the frame in accordance with the repetition of lugs 34 and 35 and ties 33. Resting on the series of pillar blocks 45 is a rigid shaft extending from the rear to the front of the apparatus; and, likewise, resting on the series of pillar blocks 4| is another rigid shaft also so extending. The righthand' shaft is designated 42, the lefthand 43. Each shaft serves as a traction rail (see below) and each shaft is secured rigidly and nonrotatably to each pillar block of its related series by means of screws 44, each of which is passed upwardly through the cross tie 3'! and through the center of the pillar block to engage a tapped bore in the underside of the shaft. See Fig. 2.

Figs. 3 and 4 show clearly the tracks provided by the bars 33 and 35 and by the shafts 42 and 43. It will be seen in Figs. 2, 3 and 4 that the track provided by the bars is of wider gage than that provided by the shafts, and, in Fig. 2, that the former track is lower in level than the latter.

A rigid frame, designated in its entirety as 45, is suspended from the track provided by the shafts 42 and 45 by means of brackets 45 and 41 each provided with a pair of V-wheels rotatably mounted on one of the shafts. See Fig. 1, wherein only bracket 46 is seen. In Figs. 2 and 3 both brackets are seen. Bracket 46 is secured to the upper righthand corner of the frame 45, and bracket 41 is secured to the opposite upper corner (of. Fig. 2). The brackets are opposite hand to each other but otherwise alike. The forward V-wheel of bracket 46 is designated 48, the rear wheel, 49; the forward wheel of bracket 41 is designated 55, the rear wheel, (see, particularly, Fig. 3) Each V-wheel is rotatably mounted on a stub shaft 52 which is rigidly secured to the related bracket (cf. Figs. 2 and 3).

Thus the frame 45 is actually a car which may be rolled backward and forward on thetrack provided by shafts 42 and 43. Details of the rest of the structure of frame 45 are discussed subsequently, it appearing desirable, now, to discuss, briefly, another frame, also suspended from the same track, and similarly provided with wheels whereby the frame may be rolled backward and forward like frame 45, so that means for motivating the two frames may be described to show, generally, the photographic codperation between the two frames.

Another rigid frame 53; so designated in its entirety, is suspended from the track provided by shafts 42 and 43 by means of brackets 54 and 55 each provided (like brackets 46 and 41) with a pair of \'wheels rotatably mounted on one of the shafts. See Fig. 1, wherein only bracket 54 is seen. In Fig. 4 both brackets are shown. Bracket 53 is secured tothe upper righthand corner of the frame 53, and bracket 55 is secured to the opposite upper corner; but, inasmuch as there is no elevational view showing bracket 55 it will be understood from the foregoing that bracket 55 has the appearance of a mirror image of bracket 54, which latter is shown in elevation in Fig. 1. The brackets are'opposite handtoeach other but otherwise ali'ke. The'forward'v -wheel of bracket 54 is designated 56, the rear-wheel, 51; the forward wheel of bracketis designated 58, the rear wheel, 59 (see, particularly, 1 Fig. 4). Each V-wheel is rotatably mounted on a stub shaft which is rigidly secured to the related bracket (of. Fig. 4).

Thus the" frame 53, like the frame 45, is actually a car which may be rolled along the track similarly to acar'of suspended tramway.

Further description of frame 53 will be deferred for reasons set forth above so that means for motivating the frames to vary their relative position, anteriorly and posteriorly, with respect to each other, may now be described.

Journ'aled at the rear in a bearing 5| which is secured to the channel 21 and at the front in another bearing 62 which is mounted on a special tie member 63 is a fore-and-aft screw 64. See, particularly, Fig. 3. Journaled at the rear in a bearing 65 which is also secured to channelll adjacent bearing 5| and at the front'in'another bearing 66 which is secured to the channel 35 is a shaft 61, the rear portion 58 of which is smooth and the fore portion of which is threaded and is designated 69. The shaft 61 may be madein'two parts, the rear portion 68 actually being a separate shaft and the forward portion 63 being a screw (similar to screw 64), the two parts'being coupled together'in alignment intermediate of the apparatus (however, no couplingis shown in the drawing). See (for shaft 57) Figs. 1, 3, and 4. The screw 54 is obscured in Fig. 1 by shaft 51. Screw 54 and shaft 6'! are on the same level and are, of course, as shown in'Fig. 3, parallel to each other, the former being slightly to the left of center of the apparatus and the latter an equal distance to the right thereof.

Mounted on frame 45 on the top front thereof is a bracket 10; seen in enlarged rear elevation in Fig. 4, the bracket being securedto the'top of the frame by means of cap screws H. A thickened portion of the bracket 10 extends above the frame 45 and is horizontally bored and tapped 'to receive, rotatablygthe screw 64. Thus, by itself, the bracket 70 operates as a feed nut for the frame 45; but it is particularly desired herein to avoid any back lash when moving the frame 45 backward or forward" to a new setting. For this reason anauxiliary nut 12 ,is provided and mounted on the screw 64 slightly forward of bracket i0. Three pins 13, the rear portions of which are threaded, are passed through the'auxiliary nut 12 'at'intervalsof surrounding'the screw 64 and are screwed intothe bracket '15; and, surrounding-each pin 13, is provided a compression spring 14 which, with its cooperating springs; exerts constant tension upon both'the auxiliary nut "and the bracket 10. Due tothe pins 13 it will be clear that the nut' '.'2 cannot rotate relative to the bracket 10. hus it will be seen that the, arrangement comprising the bracket, nut, pins, and springs, maintains the bracket threads against the forward sides of'the threads of screw 64 and the nut threads against the rear sides of the threads of the screw so that slip in the nature of back lash is prevented.

Mounted on frame 53 on the top front thereof is another bracket 15 which'is a duplicate of bracket 10. The bracket 15 is secured to the top of frame 53 in a manner similar to that in which bracket 10 is secured to frame 45. Bracket 15, however, is secured'to frame 53 so'that the forward, or threaded, portion of shaft 51 may pass through the tapped bore of the bracket; thus bracket 70 is slightly to the right of center of the apparatus and bracket I equally distant to the left thereof. The bracket I5, by itself, operates as a feed nut for the frame 53; but, to prevent back lash, an auxiliary nut 16 (equivalent to nut 12) is provided, and is connected with bracket 15 by means of three pins TI and compression springs I8 respectively equivalent to pins 13 and springs I4. The feed structure of frame 45 is duplicated in that of frame 53; and Figs. 3 and 4 are fully illustrative of both structures.

Mounted on the righthand end of the frame comprising channels and 2! at the rear of the apparatus is a motor I9; and, on the lefthand end of the same frame, is a motor 80. The former is for the purpose of driving the shaft 01; the latter for the purpose of driving the screw 64. Journaled in the webs of. channels 26 and 21 and extending between them is a shaft 8I on the right of the frame; and on the left thereof is a simi- 1 larly journaled and disposed shaft 82. See Fig. 3; also, Fig. 2.

A chain 83 connects a sprocket 84 mounted on the armature shaft of motor 19 with a sprocket 05 mounted on shaft 8I; and another chain 86 connects a second sprocket 81 also mounted on shaft 8| with a sprocket 88 mounted on the rear end of shaft 67. See, particularly, Fig. 3; also, Fig. 2.

Thus rotary motion is transmitted from motor I9 to the shaft 01.

A chain 89 connects a sprocket 90 mounted on the armature shaft of motor 80 with a sprocket 9| mounted on shaft 82; another chain 92 connects a second sprocket 93 also mounted on shaft 82 with a sprocket 94 mounted on the rear end of screw 54. See, particularly, Fig. 3; also, Fig. 2.

Thus rotary motion is transmitted from motor 80 to the screw 64.

Means for selectively operating the motors and for reversing the same are provided, and may be mounted conveniently upon the apparatus. The movement of frame 53 is of course a function of the rotation of shaft 8!, and a dial 95, mounted on the rear end of said shaft, may be calibrated and provided with a suitable marker so that the photoengraver may guide himself in the operation of motor 19. So, too, is the movement of frame 45 a function of the rotation of shaft 82, and a dial 96, mounted on the rear end of said shaft, may be calibrated and provided with a suitable marker so that the photoengraver may guide himself in the operation of motor 80. It will be understood that behind the camera, when the same is installed, is customarily a dark room; and that during exposure of a plate it is not possible to see either frame 45 or frame 53 from the rear of the apparatus; and indicators of the relative positions of the two frames are required for blind focusing. 1

A chain 97 connects a third sprocket 98 mounted on shaft ill with a sprocket 99 mounted on a stub shaft I00 suitably journaled on a bracket IOI secured in any suitable manner to the right side of the plate and screen housing I02 of the camera (see below). A handwheel I03 is mounted on stub shaft I00. By means of the handwheel I03 the operator may advance or retract frame 53 without using motor I9.

A chain I06 connects a third sprocket Hi5 mounted on shaft 82 with a sprocket I05 mounted on a stub shaft it! suitably journaled on a bracket i023 secured in any suitable manner to the left side of the plate and screen housing 02. A handwheel I09 is mounted on stub shaft I01.

By means of the handwheel I09 the operator may advance or retract frame 45 without using motor 80.

The arrangements described in the last two paragraphs provide for Vernier adjustments, as will be apparent.

By means of a pair of clamps I I0 a standard III, preferably a steel tube, is secured to and supported by leg I2 (cf. Fig. 1). Also by means of a like pair of clamps II2 another standard II3, similar to standard II I, is secured to and supported by leg I4 (cf. Fig. 1). On the top of standard III is fixed a mounting plate H4 and carried on this mounting plate is a member II5; and on top of standard H3 is fixed a similar mounting plate H6 and carried on this mounting plate is another member H5. The members I I5 may be secured to their respective mounting plates in any suitable manner, as by a clamp II'I (see Fig. 2). The members II5 are preferably castings hollowed to receive by forcefitting the ends of an I-beam IIB which extends from the rear to the front of the apparatus.

By means of a pair of clamps II9 a standard I20, similar to the abovedescribed standards III and II3, is secured to and supported by leg I3 (illustrated best in Fig. 2, standard I I I obscuring standard H9 in Fig. 1; cf., also Fig. 3). Clamps I2I secure a fourth standard I22 (shown in dotted f lines only, cf. Fig. 4; obscured by standard H3 in Fig. 1) to leg I5. Standards I20 and I22 are surmounted by cap plates and members II5 like the other standards. Another I-beam I 23, force fitted into the members II5 above standards I20 and I22, and corresponding to I-beam II 8, and extending from the rear to the front of the apparatus together with the lastnamed I-beam forms a hanger system for a floodlight carriage more particularly described below.

Beneath each I-beam is secured a C-shaped channel: that on the right of the apparatus and relating to I-beam I I3 is designated I24; that on the left and relating to I-beam I23 is designated I25. See Fig. 2. I-beam I23 is obscured by I-beam I I8 in Fig. 1. The I-beams and their related channels are seen in cross section in Fig. 2. In Fig. 4 I-beam I23 and its channel I are partly broken away. Each C-shaped channel is open downwardly. The inner surfaces of the flanges of the channel serve, as will be presently made clear, as traction rails.

By means of brackets I26 another C-shaped channel similar to channel I24 and parallel thereto is suspended from I-beam H8; and by means of other brackets I26 another C-shaped channel similar to channel I25 and parallel thereto is suspended from I-beam I23. See Fig. 2; also Figs. 3 and 4. No part of the above described structure relating to the I-beam I 23 is visible in Fig. 1

-'. because the structure on the righthand side of the apparatus obscures that on the lefthand side. Channels so supported by brackets I26 are hoods for bus bars and are open at the bottom so that a shoe on either side of the floodlight carriage may pick up current from said bars.

Adapted to run along channel I24 is a fourwheeled trolley I2], and, adapted to run along channel I25, is another four-wheeled trolley I28; both trolleys are similar, and are rigidly connected together by means of a horizontal frame I29. At the righthand and lefthand end of the frame I29 is a suspended vertical bar I (see Fig. 2 particularly; also Fig. 1, wherein only the righthand bar I30 is seen). Each vertical bar I30 is adapted to carry, adjustably, a arc floodlight irrthe 1usual' manner. The onlyfloodlight L shown in the drawing is that ion the righthand tied,;to th'ecopyboard so'th'at itmoves with the latter (see below).

The frame 45'is adapted to support'a lens board on'which is mountedsuitable mechanism con trolling the lens, filter, compensating glass flashlight; and other cameraclements associated with the'shutter; and while suchimechanism'coul'd be :so supported otherwise, the frame 15 is specially adapted to support mechanism described and claimed in my copending United States application for patent Serial No. 90,312, filed Apr. 29,

However, for the purposes of the present disclosure, it is sufiicient to set forth that the frame 45 supports "a shutter l3! (see Fig. 2) a lens bar- 'rel I3la,:'a flashlight 132 (see Fig. 1) and a'filter (not illustrated), and such other parts as'are usual: in a camera of the type described.

The frame 53 isadaptedto carry a copy board. The copy board itself is,of course, no part of the present inventionbut the means for driving the same are 'herewithin included; and are subsequently described.

The bellows ofthe-camera'obscura are indicated in dotted lines in Fig. 1 and are designated The general housing for the plate and screen series; a pair of rails, one rail being supported by all blocks of one series and the other rail being rted by all blocks of the other series; two ges reliably mounted on said rails; a lens mounted on one carriage; and a copy mounted on the other carriage.

camera having a beam mounted thereon; a plurality of transverse ties each adjustably suspended from said beam; two parallel series of laterally adjustable pillow blocks mounted on said ties with a block of each series on each tie and the blocks of one series aligned with the blocks of t e other series; a pair of rails, one rail being supported by all blocks of one series and the other rail being supported by all blocks of the other series; two carriages reliably mounted on said rails; a lens board mounted on one carriage; and a copy board mounted on the other carriage.

3. In a camera of the class described ,the combination of claim 1 including shock absorbing supports for said bridge member.

4. in a camera of the class described, the combination of claim 2 including shock absorbing supports for said bridge member.

5. In a camera of the class described, the combination of claim 1 including a pair of feed screws, each screw driving one of said carriages.

(5. In a camera of the class described, the combination of claim 2 including a pair of feed screws, each screw driving one of said carriages.

'7. Inca camera of the class described, the combination of claim 1 including a pair of feed screws, each screw driving one of said carriages; and means mounted on each carriage for preventing backlash thereof with respect to its feed screw.

8. In a camera of the class described, the combination of claim 2 including a pair of feed screws,'each screw driving one of said carriages; and means mounted on each carriage for preventing backlash thereof with respect to its feed screw.

9. In a camera of the class described, the combination of claim 1 wherein said rails are round, and wherein said carriages are provided with V- wheels engaging said rails.

10. In a camera of the class described, the combination of claim 2 wherein said rails are round, and wherein said carriages are provided with V-wheels engaging said rails.

11. In'. a camera of the class described, the combination of claim 1 including a pair of feed screws, each screw driving one of said carriages; means mounted on each carriage for preventing backlash thereof with'respect' to its feed screw; and indicators each thereof actuated in response to rotation of one 'of said feed screws and each calibrated in terms of axial distance measured on its respective screw.

12. In" a camera ofthe class described, the combination of claim 2 including a pair of feed screws," each screw driving one of said carriages; means mounted on each carriage for preventing backlash thereof with respect to its feed screw; and indicators each thereof actuated in response to rotation of one of said feed screws and each calibrated in terms of axial distance measured on its respective screw.

13. In a camera of the class described, the combination of claim 1 including means for driving said carriages independently on said rails.

14. In a camera of the class described, the combination of claim 2 including means for driving said carriages independently on said rails.

15. In a camera of the class described, a trestle structure; a bridge member resiliently mounted thereon; a plurality of transverse ties mounted on said bridge member; two aligned series of pillow blocks, with one block of one series mounted on one side of each tie and with one block of the other series mounted on the other side of each tie; a pair of rails, one rail supported by all blocks of one series and the other rail supported by all blocks of the other series; two carriages rollably mounted on said rails; a lens board mounted on one carriage; a copy board mounted on the other carriage; means for independently driving said carriage on said rails; laterally adjustable standards mounted on said trestle structure; a track mounted on said standards; and a light carriage rollably mounted on said track, said light carriage being linked to said copy board.

16. In a camera of the class described, the combination of claim 15 wherein said rails are round.

17. In a camera of the class described, a trestle structure a bridge member resiliently mounted thereon; a plurality of transverse ties each ad- ,iustably suspended from said bridge member; two aligned series of pillow blocks, with one block of one series mounted on one side of each tie and with one block of the other series mounted on the other side of each tie; a pair of rails, one rail supported by all blocks of one series and the other rail supported by all blocks of the other series; two carriages rollably mounted on said rails; a lens board mounted on one carriage; a copy board mounted on the other carriage; means for independently driving said carriages on said rails; laterally adjustable standards mounted on said trestle structure; a track m0unted on said standards; and a light carriage rollably mounted on said track, said light carriage being linked to said copy board.

18. In a camera of the class described, the combination of claim 15 wherein said means comprise two independently rotatable feed screws each thereof engaging one of said carriages mounted on said rails.

19. In a camera of the class described, the combination of claim 17 wherein said means comprise two independently rotatable feed screws each thereof engaging one of said carriages mounted on said rails.

20. In a camera of the class described, the combination of claim 17 wherein said rails are round.

21. In a camera of the class described, the

combination of claim 15 wherein said rails are -,3

23. In a camera of the class described, the combination of claim 15 wherein said means comprise two independently rotatable feed screws each thereof engaging one of said carriages mounted on said rails, and including means mounted on said last named carriages for preventing backlash of said last named carriages with respect to their feed screws.

24. In a camera of the class described, the combination of. claim 17 wherein said means comprise two independently rotatable feed screws each thereof engaging one of said carriages mounted on said rails, and including means mounted on said last named carriages for preventing backlash of said last named carriages with respect to their feed screws.

HERBERT GELB.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,033,404 Huebner July 23, 1912 1,597,598 Jones Aug. 24, 1926 1,847,010 Koppe Feb. 23, 1932 2,150,974 Huebner Mar. 21, 1939 2,356,960 Wekeman Aug. 29, 1944 2,376,416 Campbell May 22, 1945 2,441,687 Crockett May 18, 1948 2,519,609 Sussin Aug. 22, 1950

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